Start by preheating the oven to about 350 degrees F. (That's Gas Mark 4 or 175 C.)
Butter a bundt pan and coat with prepared breadcrumbs.
Use a stand mixer or hand mixer to beat the butter and sugar together until light, fluffy and pale, about 1 to 2 minutes.
Add the eggs, one at a time, beating to fully incorporate before adding another.
Sift the dry ingredients together in a bowl, and then gently stir them into the wet ingredients.
Finally, add the mashed bananas and coffee, stirring to combine. Do not over-mix.
Use a spatula to scrape the batter into a prepared pan and bake for about 40 minutes, until the top is golden brown.
Notes
Allow the Banankaka to cool for a few minutes in the pan, and then tip it out of the pan onto a cooling rack to finish cooling.Once completely cool, dust with powdered sugar (optional, but extra nice).It's best served completely cooled, but fresh, within a day or two of baking. Don't cut the cake while it's still hot, that ruins the internal texture.